Hydrogen Powered Electric Car Charging Points

[northernmonkey]

I don't think you can get a negative EROEI with the formula I am thinking of. I think in terms of EROEI > 1 is when you get more energy back than either the energy input to run your 'energy harvesting equipment' or the energy required to make your 'energy harvesting equipment'. There's a bit of difference between the two.
EROEI < 1 for the former is acceptable if you have an infinite energy source like the sun, or your energy produced is in a better form (i.e. more storable) than the energy input - think of making petrol from sunlight.
EROEI < 1 for the latter (energy harvesting equipment) makes no long term sense.

Hope you all get my line of thinking. There's at least two types of EROEI (and probably a few more like ESOEI for storage equipment like batteries or pump storage) and they will have different consequences for mankind.

You could also be a country like Australia that has little oil reserves of its own and spends a considerable proportion of its exports on importing petroleum (like 25%) but has a lot of solar energy and decides (based on both economic and national security reasons) to use EROEI < 1 energy conversion equipment to turn sunlight into petrol via water and CO2 from the air.

Hydrogen will be needed to produce ammonia for fertilisers and there's no real carbon neutral alternative to that.

I understand the infinite supply argument (the sun). The point I am making is that the sun's energy has already been captured (positively in EROEI terms) by photovoltaics in a form that is readily usable (electricity). Therefore, there is no requirement, other than in very particular circumstances, to consume hydrogen as an energy source or, again in very particular circumstances, keep it as an alternative energy store. Electricity is both vastly more convenient as an energy source and vastly easier (not to say less energy wasteful in terms of EROEI) as an energy store.

As for fertilizers from hydrogen (ammonia), that is indeed a definite use case for hydrogen. But, that is as a specialist commodity, not as a general use energy source. Gas welding would be another example that does, indeed, directly involve the consumption of hydrogen as an energy source. But, that is, arguably, an even more specialist use of the hydrogen. As you can see, these are very specialist use cases.

Name something that is needed on an everyday basis by people that needs energy to run that the large scale capture and storage of hydrogen might be used for that electricity is unable to provide.

[johnny]

To repeat, when the EROI of a source of energy is less than or equal to 1 (not 0), that energy source becomes a net "energy sink", and can no longer be used as a source of energy.
The EROEI of photovoltaics is above 1 (how much above 1 is a matter of debate). When the electricity produced in said manner is then employed to extract hydrogen from water, the EROEI is significantly below 1. Significantly enough, in fact, that the total, cumulative EROEI, from solar to hydrogen (due to the energy losses incurred in the two energy transfers) is below 1.

Your claim was EROEI<0. I objected. You didn't seem to cover how this claim is possible in your more detailed explanation. I will wait patiently, should an explanation present itself.

I will only add that the use of EROEI within the oil and gas industry has been one of the more hysterically uninformed and useless metrics ever brought up during the peak oil days. That however is not an equation, just an informed observation from a long time observer.